1. Field of the Invention
This invention relates to circuit structures having an integrated circuit flip mounted on a base substrate having metalization connected to the integrated circuit. More specifically, it relates to such an integrated circuit having a plurality of devices, with interconnection between the devices being provided by metalization on the substrate.
2. Related Art
Because GaAs integrated circuits are comparatively expensive, it is common to make microwave and millimeter (mm) wave circuits as hybrid circuits. The active devices that require the use of GaAs are fabricated on GaAs chips which are then mounted on a motherboard having a less expensive substrate, such as silicon, Al.sub.2 O.sub.3, BeO, and AlN.
Conventional circuits having a plurality of active devices are made by fabricating a separate integrated circuit or chip for each of the active devices. Circuit metalization and passive devices are printed on the motherboard and each chip is then mounted at an assigned site on the motherboard. The integrated circuit on the chip can be very simple, such as a single FET. It may also be more complex, incorporating a variety of devices to provide an overall function, such as is provided by an amplifier.
A complex circuit may require that numerous such chips be made and mounted. The resultant requirement for individual handling of small chips also tends to make the fabrication process somewhat costly. Alternatively, when a chip has a complex circuit, it is more expensive to make since it requires a larger GaAs substrate than its more simple cousin, and the benefits of hybrid circuit structure are not as fully realized.
There is thus a need for a method of hybrid circuit construction, and thereby a hybrid circuit structure that, when applied to microwave and mm-wave circuits, minimizes the size of GaAs substrates used and is simple to fabricate, thereby providing for efficient fabrication at reduced cost.